Surrounds For Music

I have two Era 300's setup as surrounds with my arc and sub. I have two questions about these.

1. They don't exist in the app as speakers that I can just play music from on there own. When they are set up as surrounds do they not exist as stand alone speakers anymore?

2. If I listen to music using my surround group I get great sound from the bar but I'm only getting sound out of one of the two Eras and it cuts in and out. So I need to try to re-set them up? They work fine as surrounds with the TV.

Thanks!